I have a table that has 2 columns : Balance , RateCol

I want to make a query, with condition like this

X is 2.25
when Balance > 0 then Total = Balance, and RateCol > X
When Balance > 2000000000 then Total = Balance - 2000000000, and RateCol <= X

The first thing I tried is using CASE , but the result is not like what I wanted

Query :

SELECT 
    Balance, 
    CASE 
        WHEN Balance > 0 AND RateCol > 2.25 THEN Balance
        WHEN Balance > 2000000000 AND RateCol <= 2.25 THEN Balance - 2000000000 
    END AS Total,
    RateCol
FROM
    MyTable

Result:

As you can see from my result, the anomalies somehow also get included even thought it's outside of my defined scope.

What I thought is this happening because I didn't defined ELSE for condition I didn't specify, but I only need result from the condition I did specify, is there a way to achieve this?

I've also tried to add WHERE on my query like this :

SELECT 
    Balance, 
    CASE 
        WHEN Balance > 0 THEN Balance
        WHEN Balance > 2000000000 THEN Balance - 2000000000 
    END AS Total,
    RateCol
FROM  
    MyTable
WHERE
    RateCol = CASE 
                  WHEN Balance > 0 THEN RateCol > 2.25
                  WHEN Balance > 2000000000 THEN RateCol <= 2.25

But CASE cannot take comparison expression, and I don't know what to do anymore

Expected result :
| Balance | Total | RateCol |
| ------------ | ------------ | ------------ |
| 4428600457.50 | 2428600457.50 | 1.400000 |
| 15339365000.00 | 15339365000.00 | 3.250000 |

(Anomalies not included)